Strength training is the fastest way to build muscle and see results — here's how often you should strength train to build muscle and avoid injury

• Any type of exercise will help build muscle, but if you want to see muscle growth, faster, then strength training is the way to go.
• Opt for a strength training program three times a week with at least a full day of rest in between.
• If you're not seeing results as fast as you like, it may come down to factors like age, gender, or protein intake.
• This article was medically reviewed by Joey Thurman, CSCS, CPT, FNS, a Chicago-based fitness expert and MYX Fitness coach.

If you're looking to jump-start muscle growth, beginning a new routine that challenges your muscles is key. You'll probably feel shaky during those first few sets, but as the brain and body begin to adapt to your new exercise routine, you'll gain strength as long as your training is consistent, especially over the first few weeks.

"The most conventional exercise to induce muscle growth is resistance (strength) training, but other types of training such as rowing (a hybrid aerobic and strength sport), pilates, and bodyweight exercise also induce muscle growth," says Kristin Haraldsdottir, PhD, Director of Exercise Research & Innovation for Hydrow.

Building muscle won't happen overnight, but with the right fitness and nutrition regimen, you can start to see results in just a few months. Learn more about muscle grwoth and some exercises that can ignite growth.

How long it takes to build muscle and see results

Gaining muscle is a slow process. It can take about three to four weeks to see a visible change. You'll see some real results after 12 weeks, but it "all depends on your goals, and what type of strength training you are doing," says Haroldsdottir.

Muscles are made up of two different types of individual muscle fibers: type one and type two.

• Type one muscle fibers, also known as slow-twitch muscle fibers, are aerobic. They're resistant to fatigue and focused on smaller movements that can be sustained for long periods.
• Type two muscle fibers, also known as fast-twitch muscle fibers, get tired more easily but allow for more powerful movements. Type two muscle fibers contain more blood supply than type one fibers.

Haroldsdottir says endurance and aerobic exercise builds more type one muscle fibers, while strength training builds more type two muscle fibers. That means you'll likely see results with muscle growth faster with strength training than other types of exercise.

You should be working out your whole body for muscle gains. Focus one day on upper body workouts, one day on your core, and one day on your lower body. Concentrating on one muscle group per workout will allow time for your muscles to rest and repair, which is also important for building muscle.

The American Center for Sports Medicine recommends you get at least eight hours of sleep nightly and rest for a minimum of 48 hours in between highly intense workouts. However, that doesn't mean you need to stop exercising for those 48 hours. You just need to rest the muscle group you worked out. During your rest days, you can try foam rolling, yoga, joint mobility exercises, and massage.

Exercises for building muscle

Haroldsdottir recommends a whole-body approach to strength training. This includes a focus on functional strength and mobility. Here are some of those exercises and the muscle groups they work:

• Glute bridges: abs, hamstrings, and lower back
• Squats: glutes, quads, hamstrings, calves, and abs
• Push-ups: chest, shoulders, abs, and triceps
• Lateral lunges: glutes, hamstrings, and quads
• Planks: whole body
• Reverse lunge with rotation: whole body
• Bent over row: back, shoulders, and arms
• Single leg Romanian deadlift: whole body

"A great way to start a strength training program is three times a week, with at least a full day of rest in between," says Haroldsdottir. "Pick four to six exercises and start with eight to 10 repetitions of each. Make sure you give yourself one to two minutes between sets, drink lots of water, and consider working with a trainer if you're unsure about your technique."

When these exercises become easy, you can increase your reps or increase the weights. If you want to build your muscles faster, go with the increase in weights.

There are numerous fitness tools to use beyond weights and machines to have an impactful workout. Haroldsdottir recommends incorporating the following items:

1. Low wood box or step: for bodyweight or weighted step-ups
2. Resistance bands
3. Yoga block
4. Weighted medicine ball
5. Bosu ball
6. Therapy ball
7. Yoga mat

How to build muscle fast

A 30-minute workout is enough to build muscle and maintain functional strength. If you want to focus on powerlifting and bodybuilding, you may opt for a 60-minute workout or longer.

However, the duration of the workout doesn't matter as much as the number of sets per week and the mechanical stress that occurs in a given session. To induce muscle growth, aim for 10 to 20 sets per week, per body part. Cardio can help build muscle, too, but it will be slower than strength training.

"People who have more muscle burn more calories, in general, because they have more tissue that requires fuel," Haroldsdottir says.

Don't forget about progressive overload. Gradually add sets, weight, or reps to increase stress on the body and to keep building muscle. For example, if you're lifting 10-pound dumbbells, you might find it difficult at first. After a time, lifting those dumbbells will start to get easier because you're building muscle and getting stronger. If you continue to lift those 10-pound dumbbells you're not going to build muscle. You'll stay the same. You have to make your regimen more strenuous again.

Why you might have a hard time gaining muscle

Several factors contribute to muscle gain — and sometimes loss — including age, gender, and protein intake.

Age: Building muscle and strength becomes more challenging starting at age 40 when your body naturally starts to lose muscle mass. Regular resistance training can fight this decline, says Haroldsdottir.

Gender: Males and females differ in their metabolism, types of muscle fibers, and speed of muscle contractions. While men are thought to grow muscle faster, women's muscles may recover faster and are slower to fatigue after workouts.

Protein: To gain muscle you need 0.5 to 0.8 grams of protein per pound of body weight per day. If you're not seeing the results you want, check to make sure you're getting enough protein in your diet, as it's essential for muscle growth.

Hormones: Hormones are responsible for controlling many physiological reactions in your body including energy metabolism, tissue growth, and growth or decline of muscle protein. Hormones, such as insulin, contribute both to building new muscle and helping to burn fat. Testosterone helps repair muscle protein after exercise; cortisol, human growth hormone (HGH), and others also play roles in muscle growth.

Progressive or volume overload: Research has shown that continuously increasing the amount of weight and reps while strength training may help build strength and muscle mass, though results vary depending on sex, age, and muscle groups worked.

Takeaways

You can build muscle with any type of exercise, but if you want to see those gains faster, strength training is the way to go.

Make sure you're getting enough protein to fuel the muscle growth, getting enough sleep every night, and resting your muscle groups in between workouts.

You won't see immediate changes in your body, as it can take up to 12 weeks for notable muscle gain due to working out.

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